Unified fire crews, stationed in the new Station No. 104 across the street, responded within moments of the alarm and found the school filled with smoke, Fitzgerald said. The firehouse opened in January.

The fire was contained to one alarm, Petersen said. No one was in the building at the time, and the cause of the fire has not been identified.

The sprinklers were only triggered at the scene of the fire. No other areas of the school experienced water damage.

"It worked perfectly," Petersen said. "We're very happy with the response, how quickly it was contained and put out."

Granite School District officials confirmed that classes at Olympus Junior High will be held as scheduled Friday.